We are analyzing the role of FGF and FGF receptors in stomach tumors using both DNA and antibody probes. Immuno-histochemistry of normal mouse gastrointestinal tissues shows localization of FGF receptor to the proximal small bowel and stomach. The ability of our antisera to react in immunohistochemistry will allow us to determine the usefulness of overexpression in diagnosis or prognosis of tumors with these amplifications. Future analysis may include immuno-histochemistry studies of primary human stomach, colon tumors or other tumor types that have receptor amplification.